U.S. patent application number 15/876510 was filed with the patent office on 2018-05-24 for device for light based skin treatment.
The applicant listed for this patent is KONINKLIJKE PHILIPS N.V.. Invention is credited to Babu VARGHESE, Rieko VERHAGEN.
Application Number | 20180140868 15/876510 |
Document ID | / |
Family ID | 48184248 |
Filed Date | 2018-05-24 |
United States Patent
Application |
20180140868 |
Kind Code |
A1 |
VARGHESE; Babu ; et
al. |
May 24, 2018 |
DEVICE FOR LIGHT BASED SKIN TREATMENT
Abstract
A device (10) for light based skin treatment is provided. The
device (10) comprises a light source (18) for providing an incident
light beam (21) for treating a skin (30), optical elements for
focusing the incident light beam (21) in a focal point (22) inside
the skin (30), and a skin interface element (11) for, during use of
the device (10), providing optical coupling of the incident light
beam (21) from the device (10) into the skin (30). The skin
interface element (11) comprises a transparent exit window (12) for
allowing the incident light beam (21) to leave the device (10), on
top of the exit window (12), a transparent mixture (13) of a polar
substance and an apolar substance, and on top of the transparent
mixture (13), a transparent foil (14), the transparent foil (14)
being more hydrophobic than the exit window (12).
Inventors: |
VARGHESE; Babu; (Eindhoven,
NL) ; VERHAGEN; Rieko; (Eindhoven, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KONINKLIJKE PHILIPS N.V. |
Eindhoven |
|
NL |
|
|
Family ID: |
48184248 |
Appl. No.: |
15/876510 |
Filed: |
January 22, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14381329 |
Aug 27, 2014 |
9884202 |
|
|
PCT/IB2013/051560 |
Feb 27, 2013 |
|
|
|
15876510 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 5/0616 20130101;
A61B 2018/206 20130101; A61N 2005/0643 20130101; A61B 18/203
20130101; A61B 2018/00452 20130101; A61B 2018/2035 20130101 |
International
Class: |
A61N 5/06 20060101
A61N005/06; A61B 18/20 20060101 A61B018/20 |
Claims
1. A method for optical coupling of an incident light beam from a
device for light based skin treatment into a skin, the method
comprising: applying a fluid to the skin, applying a transparent
foil to the skin provided with the fluid, applying a transparent
mixture of a polar substance and an apolar substance to a side of
the transparent foil facing away from the skin, and pressing a
transparent exit window of a skin interface element of the device
to the transparent foil provided with the transparent mixture, the
transparent foil being more hydrophobic than the transparent exit
window.
2. The method according to claim 1, wherein the fluid has a
viscosity of about 20 to about 80 mPas.
3. The method according to claim 1, wherein the fluid has a
viscosity of about 20 mPas.
4. The method according to claim 1, wherein the fluid is an organic
oil.
5. The method according to claim 1, wherein the transparent foil is
more hydrophobic than a material from which the transparent exit
window is made.
6. The method according to claim 1, wherein the transparent foil is
a covering for pulling over at least the transparent exit window of
the skin interface element.
7. The method according to claim 1, wherein the transparent mixture
has a refractive index which lies in between a refractive index of
the transparent foil and a refractive index of the transparent exit
window.
8. A method for optical coupling of an incident light beam from a
device for light based skin treatment into a skin, the method
comprising: applying a fluid to the skin, applying the transparent
foil as a separate substitutable covering to the skin provided with
the fluid, applying a transparent mixture of a polar substance and
an apolar substance to a side of a transparent exit window of a
skin interface element of the device, pressing said transparent
exit window to the transparent foil covering, the transparent foil
being more hydrophobic than the transparent exit window.
9. The method according to claim 8, wherein the fluid has a
viscosity of about 20 to about 80 mPas.
10. The method according to claim 7, wherein the fluid has a
viscosity of about 20 mPas.
11. The method according to claim 7, wherein the fluid is an
organic oil.
12. The method according to claim 7, wherein the transparent
mixture has a refractive index which lies in between a refractive
index of the transparent foil and a refractive index of the
transparent exit window.
13. A method for optical coupling of an incident light beam from a
device for light based skin treatment into a skin, the method
comprising: applying a transparent mixture of a polar substance and
an apolar substance to an inner surface of a transparent foil,
applying a fluid to an outer surface of the transparent foil,
applying the transparent foil as a separate substitutable covering
to the skin, pressing said transparent exit window to the
transparent foil covering, the transparent foil being more
hydrophobic than the transparent exit window.
14. The method according to claim 13, wherein the fluid has a
viscosity of about 20 mPas.
15. The method according to claim 13, wherein the fluid has a
viscosity of about 20 mPas.
16. The method according to claim 13, wherein the fluid is an
organic oil.
17. The method according to claim 13, wherein the transparent
mixture has a refractive index which lies in between a refractive
index of the transparent foil and a refractive index of the
transparent exit window.
Description
CROSS-REFERENCE TO PRIOR APPLICATIONS
[0001] This application claims the benefit or priority of and
describes relationships between the following applications: wherein
this application is a divisional of U.S. patent application Ser.
No. 14/381,329, filed Aug. 27, 2014, which is the National Stage of
International Application No. PCT/IB2013/051560, filed Feb. 27,
2013, all of which are incorporated herein in whole by
reference.
FIELD OF THE INVENTION
[0002] This invention relates to a device for light based skin
treatment, the device comprising a light source for providing an
incident light beam for treating a skin, optical elements for
focusing the incident light beam in a focal point inside the skin,
and a skin interface element for, during use of the device,
providing optical coupling of the incident light beam from the
device into the skin, the skin interface element comprising a
transparent exit window for allowing the incident light beam to
leave the device.
[0003] This invention further relates to a system for light based
skin treatment, a to a coupling foil and a method for providing
optical coupling of an incident light beam from a device for light
based skin treatment into a skin.
BACKGROUND OF THE INVENTION
[0004] Such a skin treatment device is, e.g., known from the
published international patent application WO 2008/001284 A2. Said
application discloses a skin treatment device with a laser source
and focusing optics. The device comprises a housing with an exit
window through which a laser beam is emitted. The exit window may
be made of a transparent material or may simply be an aperture in
the housing. The device creates a focal spot in a dermis layer of
the skin to be treated. The power of the laser beam and the
dimensions of the focal spot are selected such that laser induced
optical breakdown (LIOB) is induced in the focal spot in the skin
in order to stimulate re-growth of skin tissue and to reduce
wrinkles.
[0005] The focal spot is created at a fixed treatment depth,
somewhere between 0.2 and 2.0 mm. This depth is selected based on
the typical composition of human skin. In some cases, however, the
optimal treatment depth may be different. The optimal treatment
depth depends on, e.g., the thickness of the stratum corneum and
the epidermis. To prevent a lens effect by the skin and by the
curvature of the wrinkle, an index-matching material may be applied
to the skin in order to fill the wrinkle between the epidermis and
the exit window. The index-matching material should have an index
of refraction approximately between the index of refraction of the
exit window and that of the epidermis, preferably approximately
equal to the refractive index of the epidermis. In the ideal case,
the exit window and the index-matching material have the same index
of refraction as the epidermis, i.e. roughly 1.4.
[0006] However, the mere addition of an index-matching material in
order to prevent a mismatch in the refractive index is not
sufficient for obtaining the desired control over the light
intensity in the focal spot and over the exact position of the
focal spot in the skin. The skin surface (stratum corneum) shows
microscopic fluctuations in roughness due to vertically stacked
corneocytes. The coupling of light through the optically rough
stratum corneum, which resembles an array of micro lenses, is
difficult and results in loosely focused light beams. This causes a
decrease of the ratio of the photon density in the focal spot to
the background and a less efficient LIOB creation in the focus.
OBJECT OF THE INVENTION
[0007] It is an object of the invention to improve the coupling of
the light into the skin and the efficiency of the LIOB creation in
the dermis.
SUMMARY OF THE INVENTION
[0008] According to a first aspect of the invention, this object is
achieved by providing a device for light based skin treatment, the
device comprising a light source, optical elements and a skin
interface element. The light source provides an incident light beam
for treating a skin. The optical elements are provided for focusing
the incident light beam in a focal point inside the skin. The skin
interface element, during use of the device, provides optical
coupling of the incident light beam from the device into the skin.
The skin interface element comprises a transparent exit window for
allowing the incident light beam to leave the device. On top of the
exit window, a transparent mixture of a polar substance and an
apolar substance is provided. A transparent foil is provided on top
of the transparent mixture. The transparent foil is more
hydrophobic than the transparent exit window.
[0009] With such a skin interface element comprising different
layers with different physical, optical and chemical properties,
the coupling of the light into the skin is significantly improved.
Like in the already known optical skin treatment device, the
surface of the exit window flattens the skin. This mechanical
flattening is, however, not sufficient for obtaining the desired
efficient LIOB creation. From, e.g., the international patent
application WO 2010/031777 it is known to use a gel for reducing a
mismatch between the refractive indexes of the skin and the exit
window. Such a gel, however, does also not overcome the optical
coupling problems associated with the rough surface of the stratum
corneum.
[0010] The inventors have obtained better results using massage
oils or other types of organic oils. The strong capillary effect of
the oil improves the optical coupling between the interface element
and the top layers of the skin. It is to be noted that this
capillary effect can also be provided by other fluids having a
suitable viscosity of about 20 to about 80 mPas, preferably about
20 mPas. The capillary effect of the fluid overcomes the
microstructure variations and enables the efficient optical
coupling. The capillary effect is proportional to the surface
tension of the fluid, radius of capillary etc. . . . . Furthermore,
the action will be faster for low viscous fluids. Highly viscous
fluids can also provide the desired capillary action, however at
relatively slow speeds. This result in slight modification of the
radius of capillary as the drop of fluid is pulled along the
surface of skin, thereby enhancing the effect.
[0011] Also the contact angle that the drop of viscous fluid makes
as it comes in contact with the skin affects the speed of the
capillary action. Preferred contact angles between the fluid and
the skin are in the range 0-45.degree., and smaller contact angles
are preferred over larger angles.
[0012] According to the invention, this capillary effect is
significantly enhanced by adding the transparent and relatively
hydrophobic foil and the transparent mixture of a polar and an
apolar substance between the skin and the transparent exit window.
The transparent mixture provides for a smooth transition between
the more hydrophilic transparent exit window, which is usually made
of glass or a plastics material, and the foil, which results in a
flat foil surface. The surface of the foil and the skin allow the
applied oil to be effectively smeared throughout the microstructure
variations of the stratum corneum, resulting in uniform optical
coupling.
[0013] The transparent mixture is provided on top of the exit
window and the foil is applied on top of the mixture. Regardless of
the actual orientation of the device, `on top` means that it is the
next layer seen from the direction of the incident light beam
coming from the light source.
[0014] For optimal optical coupling between the device and the
skin, the transparent mixture should have a refractive index that
lies between the refractive indexes of the foil and the transparent
exit window.
[0015] According to a further aspect of the invention, a coupling
foil is provided for optically coupling an incident light beam from
a transparent exit window of a skin interface element of a device
for light based skin treatment. The coupling foil comprise a
transparent foil, the transparent foil at one side being provided
with a transparent mixture of a polar substance and an apolar
substance. Preferably, the foil is more hydrophobic than the
transparent material from which the transparent exit window is
made, which is typically plastics or glass. Such a coupling foil
can be used together with the optical skin treatment devices that
are already known from the prior art. The main requirement for the
optical skin treatment device is that it has a suitable exit
window, e.g. made of glass or plastics. The coupling foil may be a
dispensable product which is applied to the device just before each
skin treatment. For example, the coupling foil is a covering for
pulling over at least the transparent exit window of the interface
element of the device for light based skin treatment.
[0016] It is to be noted that the transparent foil and the
transparent mixture may be provided separately. Before applying the
covering to the interface element, the transparent mixture should
then first be applied to the transparent exit window and/or the
surface of the covering that is going to face the transparent exit
window. In a similar way the viscous fluid, e.g. massage oil or
another type of organic oil, to be applied between the skin and the
transparent foil may already be present on the transparent foil
surface or could be provided separately.
[0017] According to a further aspect of the invention, a system for
light based skin treatment is provided, the system comprising a
device for light based skin treatment and a coupling foil. The
device comprises a light source for providing an incident light
beam for treating a skin. The device further comprises optical
elements for focusing the incident light beam in a focal point
inside the skin. The device further comprises a skin interface
element for, during use of the device, providing optical coupling
of the incident light beam from the device into the skin, the skin
interface element comprising a transparent exit window for allowing
the incident light beam to leave the device. The coupling foil
comprises a transparent foil, wherein the transparent foil, at one
side, is provided with a transparent mixture of a polar substance
and an apolar substance. The transparent foil is more hydrophobic
than the transparent exit window of the device.
[0018] According to a further aspect of the invention, a method for
optically coupling of an incident light beam from a device for
light based skin treatment into a skin is provided, the method
comprising applying a fluid having a viscosity of about 20 to about
80 mPas. to the skin, applying a transparent foil to the skin
provided with the fluid, applying a transparent mixture of a polar
substance and an apolar substance to a side of the transparent foil
facing away from the skin, and pressing a transparent exit window
of a skin interface element of the device to the transparent foil
provided with the transparent mixture, the transparent foil being
more hydrophobic than the transparent exit window.
[0019] These and other aspects of the invention are apparent from
and will be elucidated with reference to the embodiments described
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In the drawings:
[0021] FIG. 1 schematically shows a skin treatment device according
to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] FIG. 1 schematically shows a skin treatment device 10
according to the invention. The device 10 comprises a light source
18 for providing an incident light beam 21 for treating human or
animal skin 30. The incident light beam 21 is typically a pulsed
laser. For example, Nd:YAG lasers with emission at 1064 .mu.m
(micrometer) are used for laser induced optical breakdown (LIOB)
skin treatment. Optical elements are provided for focusing the
pulsed laser beam 21 inside the skin 30. Part or all of the optical
elements may be provided in an interface element 11 which, during
use of the device 10, is pressed onto or makes contact with the
skin 30 to be treated.
[0023] The skin 30 comprises multiple layers with different optical
properties. The epidermis 16 is composed of the outermost layers
and forms a waterproof protective barrier. The outermost layer of
the epidermis is the stratum corneum which, due to its microscopic
fluctuations in roughness, impedes the coupling of light between
the device 10 and the skin 30. Underneath the epidermis 16, the
dermis 17 is situated. The dermis 17 comprises the collagen fibers
at which the skin treatment is aimed. The purpose of the skin
treatment is to create a focus 22 of the pulsed laser beam 21 in
the collagen of the dermis 17 in order to create microscopic
lesions which result in new collagen formation.
[0024] In the figure, part of the interface element 11 as well as
part of the skin 30 is enlarged in order to clarify its most
important aspects. The interface comprises a regular transparent
exit window 12 which is typically made of a relatively hydrophilic
material, such as glass or plastics. For optimum optical coupling,
the refractive index of the material of the exit window 12 is
preferably close to that of the epidermis. For human skin, the
refractive index typically is around 1.4.
[0025] According to the invention, some additional layers 13, 14,
15 are provided in between the exit window 12 and the skin 30.
Directly on the outer surface of the exit window 12, a transparent
mixture 13 of a polar and an apolar substance is provided. The
mixture 13 may be a gel or liquid which, due to its particular
composition, adheres well to the exit window 12 above and the foil
14 underneath. This assures that the foil 14 will remain flat and
the coupling of the light 21 into the skin 30 is optimal. As a
suitable example, the mixture 13 may comprise polypropylene glycol
(PPG) and polyethylene glycol (PEG). The transparent foil 14 may,
e.g., be a thin polyethylene terephthalate (PET) foil. For optimal
optical coupling between the device 10 and the skin 30, the
transparent mixture 13 and the foil 14 should have refractive
indexes that lie between the refractive indexes of the skin 30 and
the exit window 12.
[0026] Before use of the device 10 some oil, preferably an organic
oil, is applied to the skin 30 to be treated. For optimum results,
the amount of oil 15 to be applied should be well controlled, for
example in the order of 10-50 .mu.l (microliters). The hydrophobic
nature of the foil 14 and the epidermis layer 16 of the skin 30,
allows the drop of oil to be effectively smeared throughout the
microstructure variations of the skin 30 surface, resulting in
uniform optical coupling. Instead of oil, other fluids with a
suitable viscosity may be used.
[0027] The layers of the transparent mixture 13 and the foil 14 may
be an integrated part of the interface element 11 of the skin
treatment device 10. These layers 13, 14 and/or the complete
interface element 11 may be substitutable. The oil 15 is typically
provided separately, but may be provided from a refillable
reservoir in the device 10.
[0028] The transparent foil 14 may be provided as a separate
substitutable covering. Also the transparent mixture 13 may be
provided separately. In that event, before each use of the device
10, the user applies some amount of the mixture 13 to the exit
window 12 of the interface element 11 and covers it with a new
covering. Of course, the mixture 13 and the covering may also be
substituted after being used twice, 5 or 10 times. The covering may
be provided with the mixture 13 already applied to its inner
surface, which would make it unnecessary for the user to apply the
mixture 13 to the exit window 12 before applying the covering.
Optionally, the outer surface of the covering is already provided
with the oil 15 and the oil 15 does not have to be provided
separately.
[0029] Alternatively, the oil 15, the foil 14 and the mixture 13
are all provided separately and applied to the skin one by one
before the exit window 12 of the interface element 11 of a skin
treatment device 10 is pressed to the foil 14 covered with the
mixture 13. Or oil 15 and foil 145 are applied to the skin 30 and
the mixture is provided to the exit window 12.
[0030] It should be noted that the above-mentioned embodiments
illustrate rather than limit the invention, and that those skilled
in the art will be able to design many alternative embodiments
without departing from the scope of the appended claims. In the
claims, any reference signs placed between parentheses shall not be
construed as limiting the claim. Use of the verb "comprise" and its
conjugations does not exclude the presence of elements or steps
other than those stated in a claim. The article "a" or "an"
preceding an element does not exclude the presence of a plurality
of such elements. The invention may be implemented by means of
hardware comprising several distinct elements, and by means of a
suitably programmed computer. In the device claim enumerating
several means, several of these means may be embodied by one and
the same item of hardware. The mere fact that certain measures are
recited in mutually different dependent claims does not indicate
that a combination of these measures cannot be used to
advantage.
* * * * *